Velocity of Mass

Hi!
This is a last resort for a project that has begun to go sour. We have a project due in roughly 12 hours comprised off of an experiment that Emilie Du Chatelet held. We are measuring the effects of height & velocity by dropping steel balls, at one foot intervals, into a one and a half inch thick piece of clay.

Then measuring the depth of the impact crater with a ruler and repeating the process eight times; corresponding to eight feet. Then timing the distance for the ball to fall to the related foot. (One foot, Two Foot, Etc..)

We’re analyzing the data and came upon a couple grave mistakes. We’ve accidentally measured with inches and feet. (Blame group projects). Overall, I believe our data is completely wrong, because in theory the depth should increase up to four times, but it hasn’t.

Any ideas how we can resurrect this in time? Our main man on the project just walked out the door in frustration.